With the pressure of increasing of the operation cost and the bandwidth pressure brought by the development of data traffic, optimization of data transmission on a Backhaul becomes a hot issue concerned by operators. There currently exists two ways for optimizing the data transmission on the Backhaul: one is to perform a physical expansion on the Backhaul to increase transmission resource and the other is to compress the data transmitted on the Backhaul. The physical expansion is capable of increasing the carrying capability of the Backhaul with an increased cost. In comparison, data compression is an effective way to optimize the data transmission on the Backhaul. Content encoding is a typical method for fine-grain data compressing, and the pressure of the Backhaul may be relieved greatly if the content encoding is applied in the wireless network.
The content encoding method includes: slicing payload data on the Backhaul, recognizing repeated data slices in the payload and replacing the repeated data with a small index, to reduce transmitted amount of data. In the case where the content encoding technology is applied to a wireless network, it is necessary to dispose a pair of peer devices between a network device and a base station for compressing/decompressing the data transmitted on the backhaul. The network device includes a Radio Network controller (RNC), a Servering Gateway (S-GW) and the like. After receiving the data, the network device firstly slices the data and performs a hash calculation on the sliced data to obtain an index, then stores the index, the original data and the corresponding relationship between them and sends the small index having little data instead of the original data to the base station. After receiving the index, the base station replaces the index with the original data to achieve a data compression on the backhaul.
The index, original data and the correspondence relationship between them also need to be stored in the base station to enable the base station to replace the received index with the original data. Generally, RNC or S-GW needs to synchronize the index and original data stored therein to a peer device. In the wireless network, the relationship between RNC or S-GW and the base station is a one-to-many relationship, that is, there are many base stations acquiring the same data from RNC or S-GW. During the synchronization, in the case of network congestion, a busy link and the like, the delay of synchronization may be longer, or the synchronization data may be lost, and as a result, the base station can not decompress the data correctly.